Acritarches, Chitinozoaires et Graptolithes Ordoviciens et Siluriens de la vallée de la Sennette (massif du Brabant, Belgique)

A study of acritarchs and chitinozoans from Ordovician and Silurian deposits in the Sennette Valley between Asquempont and Ronquieres, allows the recognition of four assemblages of which the ages are respectively ?upper Arenig or Llanvirn; Caradoc; Llandovery (Telychian) and Wenlock. South of Asquempont an examination of two horizons with graptolites suggests an age of Llandeilo to lower Caradoc for the first, and of lower Caradoc for the second.